Interesting thread.
I'm not surprised that there is some friendly disagreement about how much a certain royal speaks a certain language. There are different standards as to what 'fluency' in a language is. Sometimes people say that someone else 'speaks' a language if they are functional (basics such as 'hello',' how are you', 'how much does this cost' can be said so that native speakers understand them) while others feel that you don't 'speak' a language until you can hold an intellectual conversation. For royals the question can get quite muddy as a person can be coached to give a speech competently in a foreign language, who would be lost in a real conversation and can then be called 'fluent' forever after on the basis of that one speech. Also, people gain and lose language fluency with practice and lack of practice. Someone who came to a foreign country in their adult years can actually forget how to speak their mother tongue if no one is there to speak it with and people can also brush up on languages. I would bet that information on the websites of the different countries list all the languages that the person in question EVER spoke. And someone who met them when they were in practice and expecting to be spoken to might call them fluent, while someone who met the same person at another time might say 'no way.' Which would truly be right?

Also, some (I know Americans have this tendency and I believe the French do too) tend to feel that a person cannot really speak their language if they have a thick foreign accent even if they can understand everything the person says and can be understood by them. While others are more forgiving. And a good or even great accent accent actually can little to do with true fluency. I myself am a parrot and have been like this since I was a small a child--I can repeat anything that is said to me two or three times with the same accent, whether I actually know what I'm saying or not! This is a gift when learning languages obviously--when I have learned to speak a language I sound like a native. However, I also sound like a native BEFORE I can really speak the language. So if I stick to two or three set phrases, someone could (it has happened before) believe that I speak a language when I actually do not. This has happened to me with incredibly difficult languages. Once a gentleman was teaching a class of us children a few phrases in Xhosa (this is one of the click languages from the southern part of Africa). I was about twelve. He was completely convinced from my perfect accent that I was a Xhosa speaker though confused by this because of my appearance. I was never able to quite convince him that I had no idea what he was saying and had never even heard of the language before. I am not the only person in the world who has the ability--in fact, I believe that it is not rare at all in situations where children are in a multi-lingual environment before the age of five and have to speak several languages. Other languages are later easier for them and many of them keep the ability to pronounce the hundreds of different possible sounds humans can make to communicate, which most people lose once the critical language learning years are done. Many of the royals were brought up in such environments and so I am sure there are those among who can 'parrot' like I can--and that people are then happy to attribute another language to the 'polyglot'--who does know many languages but not that particular one.
Just some thoughts.

Sorry, no. It takes me about five times as long to translate what is said on a video than to translate a written text.

Here is the speech: Prins Henriks tale - Nationalt | www.b.dk You can put it through Google translate.
I'd estimate it would take me about 45 minutes to translate that text, and as it doesn't contain anything new.... Google translate, okay?

A pre-wedding interview with HGD Guillaume and Stéphanie from ZDF, in German.ZDF Mediathek

Their German is very good, both speak fluently and have a cute (noticeable but not strong) accent.
I was surprised how confident and likeable Stéphanie comes across in this video. From the pictures I always thought she was shy and maybe even a little naive, but not at all. She seems like a really confident young woman and I think she's had an interesting career/development, speaking several languages and all.